Studies towards the synthesis of hyperireflexolide A

• G. Hari Mangeswara Rao

Beilstein J. Org. Chem. 2018, 14, 2106–2111, doi:10.3762/bjoc.14.185

• . Experimental procedures and analytical data Methyl 1,1,5-trimethyl-3,4-dioxohexahydro-1H-cyclopenta[c]furan-5-carboxylate (8): To a solution of the γ-lactone-fused cyclopentanone 6 (16 mg, 0.07 mmol) in dry acetone (0.4 mL) under argon was added anhydrous K2CO3 (9.7 mg, 0.07 mmol) and methyl iodide (12 mg

• . Methyl 1,1,3a,5-tetramethyl-3,4-dioxohexahydro-1H-cyclopenta[c]furan-5-carboxylate (9): To a solution of the γ-lactone-fused cyclopentanone 8 (15 mg, 0.07 mmol) in dry acetone (0.4 mL) under argon was added anhydrous K2CO3 (9.7 mg, 0.07 mmol) and methyl iodide (12 mg, 0.08 mmol) at 0 °C. The reaction was

• -dioxohexahydro-1H-cyclopenta[c]furan-5-carboxylate (4): To a solution of the γ-lactone-fused cyclopentanone 6 (75 mg, 0.331 mmol) in dry acetone (1 mL) under argon was added anhydrous K2CO3 (55 mg, 0.3972 mmol) and allyl bromide (48 mg, 0.3972 mmol) at 0 °C. The reaction was stirred at 0 °C for 21 h. Completion

Synthesis of pyrazolopyrimidinones using a “one-pot” approach under microwave irradiation

• Mark Kelada,
• John M. D. Walsh,
• Robert W. Devine,
• Patrick McArdle and
• John C. Stephens

Beilstein J. Org. Chem. 2018, 14, 1222–1228, doi:10.3762/bjoc.14.104

•  1). The heterocyclic furan and thiophene substituents allowed generation of the desired 5-aminopyrazoles in 75% and 81% yields, respectively (Scheme 1). Alkyl groups appeared to be less well tolerated, where the corresponding alkyl-substituted 5-aminopyrazoles were isolated in lower yields. With a

One hundred years of benzotropone chemistry

• Arif Dastan,
• Haydar Kilic and
• Nurullah Saracoglu

Beilstein J. Org. Chem. 2018, 14, 1120–1180, doi:10.3762/bjoc.14.98

An overview of recent advances in duplex DNA recognition by small molecules

• Sayantan Bhaduri,
• Nihar Ranjan and
• Dev P. Arya

Beilstein J. Org. Chem. 2018, 14, 1051–1086, doi:10.3762/bjoc.14.93

• heterocyclic rings such as furan 62 and 63 [126], thiophene 64 [127] and pyridine 65 (Figure 11) [128]. These conjugates exhibit potent antibacterial and antiprotozoal activity with much reduced toxicity. It was further concluded that π-stacking, H-bonding with the floor of the minor groove along with

Hypervalent iodine-mediated Ritter-type amidation of terminal alkenes: The synthesis of isoxazoline and pyrazoline cores

• Sang Won Park,
• Soong-Hyun Kim,
• Jaeyoung Song,
• Ga Young Park,
• Darong Kim,
• Tae-Gyu Nam and
• Ki Bum Hong

Beilstein J. Org. Chem. 2018, 14, 1028–1033, doi:10.3762/bjoc.14.89

• (3a–c, 3f) [31]. However, electron-rich aryl allyl ketone oximes such as 1d, 1e and 1g proved inferior. Also the furan-substituted allyl ketone oxime delivered the desired product 3h albeit in a moderate yield. In addition, various alkyl allyl ketone oximes were investigated. While cyclopropyl allyl

Fluorocyclisation via I(I)/I(III) catalysis: a concise route to fluorinated oxazolines

• Felix Scheidt,
• Christian Thiehoff,
• Gülay Yilmaz,
• Stephanie Meyer,
• Constantin G. Daniliuc,
• Gerald Kehr and
• Ryan Gilmour

Beilstein J. Org. Chem. 2018, 14, 1021–1027, doi:10.3762/bjoc.14.88

• explored (to generate 2k and 2l, respectively). Unsurprisingly, whilst the 6-membered ring formed in 42% yield, cyclisation to form the analogous 7-membered ring failed. It was, however, possible to generate heterocyclic species such as the 9-fluorenonyl-substituted oxazoline 2m (48%) and the furan 2n (59

Mannich base-connected syntheses mediated by ortho-quinone methides

• Petra Barta,
• Ferenc Fülöp and
• István Szatmári

Beilstein J. Org. Chem. 2018, 14, 560–575, doi:10.3762/bjoc.14.43

• phenolic Mannich bases, leading to the disappearance of the only aromatic ring. In a recent publication by same research group [72], they elaborated a simple route to 1,2-dihydronaphtho[2,1-b]furan and 2,3-dihydrobenzofurans via base-induced desamination. They also reported the development of a simple

Diels–Alder cycloadditions of N-arylpyrroles via aryne intermediates using diaryliodonium salts

• Huangguan Chen,
• Jianwei Han and
• Limin Wang

Beilstein J. Org. Chem. 2018, 14, 354–363, doi:10.3762/bjoc.14.23

• diaryliodonium salts can generate benzynes under severe basic conditions, the resulted benzynes were allowed to undergo cycloaddition reaction with furan or N-arylation of secondary amides and amines. Due to the easy accessibility of the diaryliodonium salts, this kind of benzyne precursor is attracting

• extensive attention [14][15][16]. Also as a five-membered heterocyclic ring, the cycloaddition reaction of N-substituted pyrroles is much less than that of furan [17][18][19][20][21]. As a matter of fact, the Diels–Alder adduct formation of pyrroles with benzyne has been postulated in 1965 as transient

Recent advances on organic blue thermally activated delayed fluorescence (TADF) emitters for organic light-emitting diodes (OLEDs)

• Thanh-Tuân Bui,
• Fabrice Goubard,
• Malika Ibrahim-Ouali,
• Didier Gigmes and
• Frédéric Dumur

Beilstein J. Org. Chem. 2018, 14, 282–308, doi:10.3762/bjoc.14.18

• 5 hours for T13-based OLEDs. A comparison established with an iridium complex, i.e., tris[1-(2,4-diisopropyldibenzo[b,d]furan-3-yl)-2-phenyl-1H-imidazole]iridium(III) (Ir(dbi)3) evidenced the relevance of the TADF approach, as a device lifetime of only 18 hours was found while operating OLEDs in the

One-pot sequential synthesis of tetrasubstituted thiophenes via sulfur ylide-like intermediates

• Jun Ki Kim,
• Hwan Jung Lim,
• Kyung Chae Jeong and
• Seong Jun Park

Beilstein J. Org. Chem. 2018, 14, 243–252, doi:10.3762/bjoc.14.16

• -alkylation compound 7e was obtained instead of the desired furan (Table 1, entry 5). It is possible to consider that the d orbitals of the sulfur atom in a sulfide group could possibly stabilize the adjacent carbanion [73][74]. To expand the scope of substituted N,S-acetals that could provide the desired

• compounds 7f and 7g, the low reactivity resulted from the decreased mesomeric effect of the furan structure: the higher electronegativity of oxygen facilitated the polarized form [71]. Among various arenes, the 4-nitrophenyl substituent 7p only afforded the desired thiophene 8p in a moderated yield (42

5-Aminopyrazole as precursor in design and synthesis of fused pyrazoloazines

• Ranjana Aggarwal and
• Suresh Kumar

Beilstein J. Org. Chem. 2018, 14, 203–242, doi:10.3762/bjoc.14.15

• -(furan-2-yl)-2-phenylpyrazolo[1,5-a]pyrimidine (168) using a similar synthetic strategy from the reaction of 5-aminopyrazole 16/126 with sodium 3-(furan-2-yl)-3-oxoprop-1-en-1-olate (167, Scheme 47). Ren et al. [108] described the synthesis of 6-aminopyrazolo[1,5-a]pyrimidine derivatives 172 involving

From dipivaloylketene to tetraoxaadamantanes

• Gert Kollenz and
• Curt Wentrup

Beilstein J. Org. Chem. 2018, 14, 1–10, doi:10.3762/bjoc.14.1

• obtained by flash vacuum pyrolysis of furan-2,3-dione 6 and dimerizes to 1,3-dioxin-4-one 3, which is a stable but reactive ketene. The transannular addition and rearrangement of enols formed by the addition of nucleophiles to the ketene function in 3 generates axially chiral 2,6,9-trioxabicyclo[3.3.1

• dimerization of dipivaloylketene (2), itself obtained in high yield by FVP of furan-2,3-dione 6 (Scheme 3). Ketene 3 reacts with a variety of nucleophiles in an addition reaction to the ketene function, thereby transforming the ketene to enol derivatives 14 or 9 of 1,3-dioxin-4-ones. Subsequently, these enols

Reactivity of bromoselenophenes in palladium-catalyzed direct arylations

• Aymen Skhiri,
• Ridha Ben Salem,
• Jean-François Soulé and
• Henri Doucet

Beilstein J. Org. Chem. 2017, 13, 2862–2868, doi:10.3762/bjoc.13.278

• allowed the coupling of several heteroaromatics such as thiazole, pyrrole, furan or imidazole derivatives with aryl bromides [36]. 2-Bromoselenophene, which was easily prepared by reaction of selenophene with N-bromosuccinimide [37], and 2-ethyl-4-methylthiazole were employed as model substrates for our

CF₃SO₂X (X = Na, Cl) as reagents for trifluoromethylation, trifluoromethylsulfenyl-, -sulfinyl- and -sulfonylation and chlorination. Part 2: Use of CF₃SO₂Cl

• Hélène Chachignon,
• Hélène Guyon and
• Dominique Cahard

Beilstein J. Org. Chem. 2017, 13, 2800–2818, doi:10.3762/bjoc.13.273

• exploited for cascade chlorination/cyclisation processes. For instance, diethyl malonates substituted by an alkyl chain bearing an alcohol or ether function could give access to tetrahydropyran or -furan derivatives [55]. Furthermore, this type of process also allowed the synthesis of diverse heterocycles

Vinylphosphonium and 2-aminovinylphosphonium salts – preparation and applications in organic synthesis

• Anna Kuźnik,
• Roman Mazurkiewicz and
• Beata Fryczkowska

Beilstein J. Org. Chem. 2017, 13, 2710–2738, doi:10.3762/bjoc.13.269

• expected ylide 97. The subsequent intramolecular Wittig reaction in boiling toluene gave the 1,2-dihydroquinoline derivatives 98, which underwent dehydrogenation into the corresponding 4-arylquinolines 99 in yields of 55–90% (Scheme 57) [70]. In an analogous manner, Yavari and Mosslemin synthesized furan

• derivatives from 2-hydroxyketones 100, triphenylphosphine, and dialkyl acetylenedicarboxylates. The intermediate vinylphosphonium salt 101 was attacked here at the β-position by the nucleophilic oxygen atom of the hydroxyketone anion. The final product of this reaction was the expected furan derivative 102

• ylides in the intramolecular Wittig reaction. Synthesis of furan derivatives via resonance-stabilized ylides in the intramolecular Wittig reaction. Synthesis of 1,3-indanedione derivatives via resonance-stabilized ylides in the intermolecular Wittig reaction. Synthesis of coumarin derivatives via

Structure–property relationships and third-order nonlinearities in diketopyrrolopyrrole based D–π–A–π–D molecules

• Jan Podlesný,
• Lenka Dokládalová,
• Oldřich Pytela,
• Adam Urbanec,
• Milan Klikar,
• Numan Almonasy,
• Tomáš Mikysek,
• Jaroslav Jedryka,
• Iwan V. Kityk and
• Filip Bureš

Beilstein J. Org. Chem. 2017, 13, 2374–2384, doi:10.3762/bjoc.13.235

• -photon absorbers (2PA). In this respect, the central DPP bicyclic lactam is often decorated with electron donors such as alkoxy- or dialkylamino groups [11][12], triphenylamine [13][14], heterocyclic carbazole [15], thiophene [16][17], furan [18], and organometallic ferrocene [19]. 2PA-active DPPs were

One-pot syntheses of blue-luminescent 4-aryl-1H-benzo[f]isoindole-1,3(2H)-diones by T3P^® activation of 3-arylpropiolic acids

• Melanie Denißen,
• Alexander Kraus,
• Guido J. Reiss and
• Thomas J. J. Müller

Beilstein J. Org. Chem. 2017, 13, 2340–2351, doi:10.3762/bjoc.13.231

• Düsseldorf, Universitätsstraße 1, D-40225 Düsseldorf, Germany 10.3762/bjoc.13.231 Abstract In situ activation of 3-arylpropiolic acids with T3P® (n-propylphosphonic acid anhydride) initiates a domino reaction furnishing 4-arylnaphtho[2,3-c]furan-1,3-diones in excellent yields. Upon employing these

• , sensing and display applications [41]. 4-Phenylnaphtho[2,3-c]furan-1,3-diones can well serve as reactive intermediates in multicomponent reactions, e.g., for synthesizing the corresponding imides. A particularly intriguing access to 4-phenylnaphtho[2,3-c]furan-1,3-diones is the intramolecular [4 + 2

• activation of benzyl alcohols in the synthesis of N-benzylphenothiazine derivatives [48], we reasoned that T3P® might be equally well suited for furnishing 4-phenylnaphtho[2,3-c]furan-1,3-diones, and thereby opening a straightforward entry to 4-aryl-1H-benzo[f]isoindole-1,3(2H)-diones in a diversity-oriented

Dialkyl dicyanofumarates and dicyanomaleates as versatile building blocks for synthetic organic chemistry and mechanistic studies

• Grzegorz Mlostoń and
• Heinz Heimgartner

Beilstein J. Org. Chem. 2017, 13, 2235–2251, doi:10.3762/bjoc.13.221

• radical intermediate 46 governs the formal [4 + 2]-cycloaddition reaction of E-1b with 3,4-di(α-styryl)furan (47, Scheme 15). The photoinduced reaction occurs via an electron-transfer (PET) process and led to the formation of the polycyclic product 48 in a stereospecific manner [52]. Similar products were

• (α-styryl)furan (47) with dimethyl dicyanofumarate (E-1b). Acid-catalyzed Michael addition of enolizable ketones of type 49 to E-1. Reaction of diethyl dicyanofumarate (E-1a) with ammonia NH3. Reaction of dialkyl dicyanofumarates E-1 with primary and secondary amines. Reaction of dialkyl

Switchable highly regioselective synthesis of 3,4-dihydroquinoxalin-2(1H)ones from o-phenylenediamines and aroylpyruvates

• Juraj Dobiaš,
• Marek Ondruš,
• Gabriela Addová and
• Andrej Boháč

Beilstein J. Org. Chem. 2017, 13, 1350–1360, doi:10.3762/bjoc.13.132

• -amino group of 11e. The opposite regioisomer 17e (ANTI) was selectively prepared by reaction of the more nucleophilic m-amino group of 11e with the most reactive lactonic carbonyl group in 5-(4-chlorophenyl)furan-2,3-dione (13) through an amide intermediate 15 (Scheme 2). Abasolo et al. studied the

• ) (natively preferring SYN regioselectivity, see Table 1, entry 4, column 3) complicated the desired reaction. The other possibility was to perform the regioselective synthesis of 17d (ANTI) from an appropriate furan-2,3-dione 13 (Scheme 2). The preparation of 13 failed in our hands. Therefore, we decided to

Molecular-level architectural design using benzothiadiazole-based polymers for photovoltaic applications

• Vinila N. Viswanathan,
• Arun D. Rao,
• Upendra K. Pandey,
• Arul Varman Kesavan and
• Praveen C. Ramamurthy

Beilstein J. Org. Chem. 2017, 13, 863–873, doi:10.3762/bjoc.13.87

• significant role in increasing the efficiency for OPVs [30][31]. However, fused π-bridges (such as thienothiophene) having a larger molecular structure and higher degree of conjugation are less explored with respect to thiophene and furan spacers. Thienothiophene ensures a highly delocalized electron system

Synthesis of ribavirin 2’-Me-C-nucleoside analogues

• Fanny Cosson,
• Aline Faroux,
• Jean-Pierre Baltaze,
• Jonathan Farjon,
• Régis Guillot,
• Jacques Uziel and
• Nadège Lubin-Germain

Beilstein J. Org. Chem. 2017, 13, 755–761, doi:10.3762/bjoc.13.74

• compound 10b. As depicted in Figure 3, compound 10b displayed an S-type conformation and an anti arrangement of the atoms O(1’)-C(1’)-C(1)-N(2) according to the dihedral angle of 0° lower than 90° (43°). Moreover, the benzyl group appeared to be present in two different positions covering the furan ring

Synthesis of 1-indanones with a broad range of biological activity

• Marika Turek,
• Dorota Szczęsna,
• Marek Koprowski and
• Piotr Bałczewski

Beilstein J. Org. Chem. 2017, 13, 451–494, doi:10.3762/bjoc.13.48

• followed by 1,5-hydrogen migration involving the o-alkyl substituent. 1,5-Diradicals 102 were formed as a result of elimination of acid HX from 1,4-diradicals 101. Finally, 1,5-diradicals 102 underwent cyclization to give 1-indanones 103 in good yields and 2-alkylidene benzo[c]furan derivatives 104 as

Poly(ethylene glycol)s as grinding additives in the mechanochemical preparation of highly functionalized 3,5-disubstituted hydantoins

• Andrea Mascitti,
• Massimiliano Lupacchini,
• Ruben Guerra,
• Ilya Taydakov,
• Lucia Tonucci,
• Nicola d’Alessandro,
• Frederic Lamaty,
• Jean Martinez and
• Evelina Colacino

Beilstein J. Org. Chem. 2017, 13, 19–25, doi:10.3762/bjoc.13.3

• 5c (R2 = furan-1-ylmethyl, Table 3, entries 6 and 10), and wet-grinding experiments with PEGs, for the series 2a, 3a, 4 (Table 3, entries 1, 4, and 7, respectively) and 5a (R2 = ethyl, Table 3, entry 8) or 2b and 6 (R2 = allyl , Table 3, entries 2 and 12). However, the PEG influence on the reaction

Chromium(II)-catalyzed enantioselective arylation of ketones

• Gang Wang,
• Shutao Sun,
• Ying Mao,
• Zhiyu Xie and
• Lei Liu

Beilstein J. Org. Chem. 2016, 12, 2771–2775, doi:10.3762/bjoc.12.275

• enantiocontrol, while the enantioselectivity for ketone 1e bearing an electron-donating group decreased. The mild process exhibited excellent functional group tolerance, with chloride (2f), fluoride (2g), and CF3 moieties (2h) well tolerated for further manipulation [46][47]. Heteroaryl ketones such as furan

A new paradigm for designing ring construction strategies for green organic synthesis: implications for the discovery of multicomponent reactions to build molecules containing a single ring

• John Andraos

Beilstein J. Org. Chem. 2016, 12, 2420–2442, doi:10.3762/bjoc.12.236

• target bond 3-partition dissection maps for 27 commonly found heterocyclic rings is given in the Supporting Information File 1 (see Schemes S6 to S32). These include benzimidazole, 2,3-dihydro-1H-benzo[b][1,4]diazepine, benzofuran, benzopyran, chromen-4-one, coumarin, cyclopent-2-enone, furan, Hantzsch